Continence, or normal control of urine retention in the bladder, involves the coordination of the bladder, bladder neck and urinary sphincter. The body stores urine in the bladder by maintaining a closed bladder neck and a contracted urinary sphincter muscle. To pass urine the bladder contracts while the bladder neck opens and the urinary sphincter muscle relaxes.
Urinary incontinence (UI) occurs when one or more of the anatomical structures related to urine storage malfunctions and leads to a loss of control of urination. The most common type of incontinence is caused by hypermobility of the bladder neck and urethra due to a weakening of the tissues surrounding these structures. In females, pelvic trauma associated with child birth is a common cause of tissue weakening. Another cause of incontinence is a deficiency in urinary sphincter muscle control, intrinsic sphincter deficiency (ISD). It is estimated that approximately 8.5 million women suffer from UI in the United States. Up to 75% of female nursing home patients experience some degree of urinary incontinence, creating a tremendous economic, as well as hygienic, burden.
Female incontinence is currently treated using devices, surgical techniques, behavioral techniques and pharmaceuticals. Devices used to treat female incontinence include absorbent pads, in-dwelling or Foley catheters, vaginal pessaries (U.S. Pat. Nos. 5,224,494, 5,007,894, 4,139,006, 3,554,184, and 3,554,184), solid continence rings (such as the Cook.TM. or Suarez continence rings), injected or implanted materials (such as Contigen.TM., based on collagen), the American Medical Services inflatable 800 artificial urinary sphincter, and inflatable urethral plugs (such as Reliance.TM.). Surgery to correct hypermobility of the urethra and bladder neck, behavioral therapy, and drugs that act on bladder neuronal control are also used to combat female incontinence.
The currently available inflatable vaginal pessaries for female incontinence do not sufficiently control incontinence in a comfortable, convenient fashion. U.S. Pat. Nos. 5,007,894 and 5,224,494 disclose inflatable donut-shaped devices. The donut-shaped device of U.S. Pat. No. 5,007,894 when inflated in the vagina transmits intra-abdominal pressure during a stress condition, such as coughing, to the upper urethra. The device has two projections on the donut shaped body to position the device on either side of the urethra in the vaginal cavity. When the donut is inflated it remains in place along the vaginal wall and is deflated for removal. The device of U.S. Pat. No. 5,224,494 is a similarly shaped donut with an additional, long, retractable inflation robe that does not protrude outside the body cavity. The device of U.S. Pat. No. 3,646,929 is an inflatable diaphragm coupled to an elongated solid support that is inserted into the vagina. These devices are difficult to insert into the vagina, uncomfortable to wear, and not likely to stay in place; furthermore they inadequately prevent incontinence or leakage of urine.
Weakening of the pelvic tissues can also result in prolapse of the uterus, bladder, rectum, or intestines. Vaginal pessaries can be used as a mechanical barrier to prevent the extrusion of these organs through the introitus. Devices such as those discussed above can be used to treat prolapses but suffer from many of the drawbacks as discussed for incontinence.